Many computing devices utilize touch surfaces, such as touch pads and touch screens. These touch surfaces may be configured to receive input from an input tool (e.g., a pen, a stylus, other input objects, etc.) as well as user touch input (e.g., finger input). When using the input tool, e.g., to write a message on the touch surface, a user may inadvertently contact a touch surface (e.g., rest his or her palm on the touch surface).